Congress:
EuroSafe Imaging 2021
Keywords:
Lung, Radiographers, Radioprotection / Radiation dose, CT, CT-Angiography, Contrast agent-intravenous, Diagnostic procedure, Radiation safety, Dosimetric comparison, Education and training, Embolism / Thrombosis
Authors:
M. Gentile, A. GUIDI, A. Fidanzio, A. Porcelli, L. Senes, L. Bonomo, A. R. Larici, C. Colosimo
DOI:
10.26044/esi2021/ESI-10569
Results or findings
Given the amount of information that the CATPHAN 600 phantom is able to provide (as opposed to the PMMA phantom which provides information exclusively related to image noise), part of the series carried out in CT 38 have been processed through QA Lite. The choice of taking into consideration the series acquired only by a scanner was dictated by the fact that, as previously mentioned, the data provided by the CT 38 and the CT 29 are almost completely superimposable.
Of course, for the pulmonary embolism protocol, the use of a low kilovoltage (such as 80 kV) is still recommended: this is because the thorax does not have organs or adipose structures that need to use a higher dose and, above all, because the presence of contrast medium does not require a high voltage which, on the contrary, would lead to a hardening of the beam with a consequent decrease in contrast resolution.
Furthermore, as can be seen in scans carried out at 80 kV but with high ASIR, the increase in noise is slightly higher and totally acceptable (11.4 compared to 10.8).
In this regard, several studies have been carried out that have shown that the use of a low kilovoltage (90 kV versus 120 kV) associated with the administration of a lower dose of contrast (40 mL versus 100 mL) does not show statistically significant differences in the qualitative assessment of vessels and organs. In fact, by decreasing the tube tension, the amount of contrast medium can be reduced without degrading the image quality.
The in-depth retrospective analysis of the acquisition parameters (Kv, mAs, noise index, CTDI, DLP, pitch, etc…) allowed to present a right dose protocol that allows to obtain diagnostic images, , and to reduce the dose as much as possible.